I flew and competed as a thumb flyer for about 20 years and switched to thumb and finger flying (with a tray) about 4 years ago. With thumb flying there is tension applied to get very precise movement of the controls. Steve Stricker at one TOC pressed so hard on the sticks he actually cut his thumbs (Futaba stick tops are pretty sharp). With finger and thumb flying I feel much more relaxed on the sticks and can practice very precise flights longer without feeling tired.